Dice have long been used to simulate the play of poker. It is well known that people commonly use several ordinary cubical dice, each marked with one to six points, to throw representations of poker hands. Since such dice have no suit attribute markings, the variety of kinds of hands that can be obtained is limited. Only hands containing a pair, two pair, three of a kind, full house, four of a kind, five of a kind, or a straight can be rolled.
A major innovation in dice for poker-like games was the use of markings similar to those on playing cards. One design that became very popular uses a cubical die that shows nine through ace on its faces. The ace is marked with a single suit symbol, often a spade. The ten is marked using a set of ten symbols of a suit. The nine is marked analogously. The remaining three faces bear designs reminiscent of those found on king, queen and jack playing cards but have no markings indicating suit. Such dice are often sold in sets of five. All dice in a set are marked identically.
Despite the fact that such dice can show no more hands than can common spotted dice, they have gained enormous popularity around the world. Many have been manufactured for over a century, and they are still to be found offered for sale. They have become classic. To many people, the term "poker dice" means such dice. In fact, The Random House Dictionary of the English Language [Unabridged Edition, copyright 1966, Random House, Inc., New York] defines "poker dice" as such. In the following paragraphs, these dice are called "classical poker dice" to distinguish them from other kinds of dice bearing playing card indicia.
Classical poker dice serve to characterize much of the prior art in the U.S. patent literature dealing with poker dice. Perhaps more importantly, classical poker dice have served as a starting point for invention. Since 1898, dice with card indicia patented in the U.S. were intended to improve the variety of kinds of poker hands by getting more and better representations of playing cards onto dice. Inventors have used dice with more than six sides and have added suit attribute markings.
For example, U.S. Pat. No. 614,524 to Yardley (1898) disclosed five decahedral (10-sided) dice bearing full likenesses of playing cards. U.S. Pat. No. 645,112 to Mapes (1900) disclosed five dodecahedral (12-sided) dice, each face of which shows both numerical and suit attribute markings. U.S. Pat. No. 809,293 issued to Friedenthal (1906) disclosed five decahedral dice with suit and numerical attribute markings.
Another shortcoming of classical poker dice is that they do not yield straight flushes.
It is easy to design even cubical dice with which one can throw straight flushes but only straight flushes. Simply place the four aces of the four suits on faces of one die; the four kings on faces of a second die, the four queens on a third die, the four jacks on a fourth die and the four tens on the fifth and last die. No matter which card indicia appear on the unspecified two faces of each die, one cannot throw hands containing four aces, four kings, four queens, four jacks or four tens. The essence of a good design for dice with playing card indicia is that both straight flushes and fours of a kind can be thrown with them.
Although this analysis and subsequent objects and description focus on the capability of dice to yield fours of a kind and straight flushes, that is not to ignore triples and pairs. The capability to throw four of a kind with dice is the most demanding level of performance of several closely related capabilities, including throwing a full house, three of a kind, two pairs, and a pair. Generally, if a set of poker dice can yield fours of a kind when thrown, it will also yield poker hands containing triples and pairs.
Interestingly, Mapes in 1900 must have recognized the value of being able to throw both fours of a kind and straight flushes because the markings on his dodecahedral dice permit both kinds of hands. But the text of his patent is silent on this feature.
In later years, inventors explicity recognized the benefits of enabling players to roll both straight flushes and fours of a kind and used dice with eight or more sides to achieve that objective. U.S. Pat. No. 3,608,905 to Edison (1971) disclosed five dodecahedral dice marked with suit and numerical attributes and claims straight flushes. U.S. Pat. No. 4,989,875 to Capy (1991) discloses octahedral (8-sided) dice marked with suit and numerical attributes in a manner to allow throwing straight flushes. In neither of these two patents, however, does the inventor specifically recognize the capability to throw fours of a kind with the same dice that allow straight flushes.
Some inventions having to do with dice with playing card indicia seem to take a step backwards. U.S. Pat. No. 1,419,056 to Kaufman (1922) disclosed a die in the shape of a fourteen-sided polyhedron, marked only with numerical attributes and lacking suit attribute markings. Several such dice could used to simulate playing poker with cards. But poker hands depending on suits for definition can not be rolled with Kaufman's dice. This invention did not therefore extend the variety of kinds poker hands that can be rolled beyond those available with the classical poker dice. It merely increased the number of numerical attributes marked on the dice.
Another approach to solving explicity the problem of being able to roll both straight flushes and fours of a kind is to change the game. U.S. Pat. No. 4,436,306 to Sanders (1984) discloses markings for eight numerical attributes combined with five suit attributes distributed over the faces of five octahedral dice. Such dice can only be used for some derivatives of the game of poker wherein the rules have been adjusted to recognize five suits. The inability of such dice to match popular understandings of the game of poker is obviously a commercial disadvantage.
Although clever in concept, dice with eight, ten, twelve, or fourteen sides bearing playing cards indicia have historically never achieved the popularity of classic poker dice despite the obvious shortcomings of the latter. Perhaps it is the unaccustomed appearance of the higher order polyhedra, or the feel of such unfamiliar shapes in a player's hand. Some patent literature--for example, U.S. Pat. No. 4,989,875 to Capy (1991)--teaches that six-sided dice have superior rolling performance that guarantees a certain level of credible randomness. The regular octahedra and decahedra have angles too pronounced to achieve a roll in a manner that overcomes the characteristics of the throw.
Another disadvantage of dice with more than six sides is that they produce proportionately fewer exciting hands and are therefore less entertaining. The following table, calculated ignoring jokers, shows the fall off in entertainment value as the number of sides is increased.
______________________________________ Entertainment Value = Number of Probability of Throwing Identification of Dice Sides Two Pair Or Better ______________________________________ Classical Poker Dice 6 48.0 percent U.S. Pat. No. 4,989,875 to 8 18.5 percent Capy (1991) U.S. Pat. No. 809,293 to 10 11.4 percent Friedenthal (1906) U.S. Pat. No. 645,112 to 12 6.9 percent Mapes (1900) ______________________________________
Whatever the reason, the vast majority of people over the decades seem to clearly prefer cubical poker dice. All prior art disclosed in U.S. patents, save one instance, are defective in this manner. That is, they involve dice with more than six faces.
The one exception is U.S. Pat. No. 4,258,919 to Martelli (1981). Recognizing the restrictions on the kinds of hands that can be thrown with six-sided classical poker dice, this patent discloses creation of a fifth suit to enrich the yield of six-sided dice. Markings for ace through nine with each of five suits are distributed across five six-sided dice in a way to permit both straight flushes and fours of a kind to be thrown. As with Sanders dice, this method is a commercial disadvantage because the concept of five suits departs significantly from the familiar character of poker.
In summary, all prior disclosed art involves dice which are unsatisfactory because they have more than six sides, do not permit throwing both straight flushes and fours of a kind or depart from popular notions of poker through the introduction of additional suits.